1. Field of the Invention
The present invention relates to an interactive drawing recognition processing method which performs a vector producing process for each pattern element, which is included in image data, for example, in order to generate a data base of an existing drawing.
2. Description of the Related Art
To construct a data base of existing drawings such as maps and diagrams of machines, there have been proposed various drawing recognition processing methods. FIG. 1 shows an example of the processing procedure of the interactive drawing recognition processing method according to the prior art. In the interactive drawing recognition processing method, a drawing is read by a scanner to create raster data (run length data) basically in the run length form (step 52). The run length data is displayed on a screen of a display. Next, to vectorize or transform each pattern or drawing elements into vectors, there is conducted, for example, a core or center line production process. In this case, when the operator specifies by a position input device or a pointing device a domain or region of the drawing to be recognized on the screen, the run length data contained in the specified domain is processed such that centers of the run lengths are connected to each other to produce a center line (step 54). Interactively conducting the core production process for the other drawing elements, there is attained vector data by performing a modification of the drawing and so forth (step 56 ). Thereafter, a character recognition is accomplished for character strings included in the drawing and a structure forming process is carried out, for example, to assign attributes to the pattern and to establish relationships between patterns, thereby producing a structured data base.
Moreover, according to a conventional line type recognition method, existing drawings such as maps and diagrams of apparatuses are first inputted to the recognition system to attain binary image data and then a vectorizing process is conducted for the binary image data. Thereafter, when a predetermined pattern is specified, a retrieval is effected with vector data for a series of patterns to be continued from the specified pattern according to a predetermined program. A check is then made to decide whether or not the attained series of patterns repeatedly includes the predetermined pattern, thereby recognizing the line type thereof.
Additionally, there has been conventionally proposed various map input systems in which a map is read, pattern elements thereof are converted into vector data, and patterns of houses are recognized to be assigned with codes. For example, in an interactive map data input system of the prior art, the map is first read by a scanner to produce binary image data. Subsequently, the operator picks by a pointing device each pattern element to transform the element into vector data. Furthermore, the operator picks each of the house patterns such that the system recognizes the house pattern and then creates a code for the pattern. Thereafter, symbols included in the map are recognized and the structure forming process is carried out, for example, to decide attributes of the patterns and to relate the patterns to each other, thereby attaining a structured data base.
However, in the interactive drawing recognition processing method of the prior art, when producing vectors from the respective pattern elements, the run length data is directly processed to generate center lines. Consequently, in the center line generating process or a medial line extraction, it is required to carry out several processes such as decisions of contours and positions of run lengths. Therefore, this leads to a problem that a long period of time is required to completely accomplish the center line generation for the pattern after the operator specifies the pattern to be recognized.
In addition, according to the conventional line type recognition method, the line type of a series of patterns is recognized at a time according to the vector data of the overall drawing and hence there exists a problem of the insufficient processing speed in the recognition. Furthermore, since the line type is recognized according to the program, any line type other than those taken into consideration in the program cannot be coped with. This causes a problem in that only a preset range of line types can be recognized.
Moreover, according to the interactive map input system of the prior art, in the process to recognize the house patterns, the operator specifies the house patterns one by one, leading to a problem that a considerably heavy load is imposed on the operator and the process can be achieved only at a low speed.